Patna: Experts Wednesday collected samples of litchi to identify the virus strain that has claimed the lives of over 50 children in Bihar.

"We have collected samples of litchi from orchards in affected areas for toxicology study. It will help us to identify the virus strain of the disease that remains a mystery till date," said Prabhat Kumar Sinha, who is heading a six-member team from the Rajendra Memorial Research Institute of Medical Sciences (RMRIMS).

"Now it will be known whether the disease was caused by litchi or not," Sinha told IANS over the phone. "In fact, the disease still remains a mystery," he said.

Some scientists, including Sinha, in their earlier reports had attributed the disease to litchies in Muzaffarpur district. "It is a subject for in-depth research," he said.

Vishal Nath, director of the Muzaffarpur-based National Research Centre for Litchi, said northern Bihar, including Muzaffarpur, accounts for over 62 percent of the country`s total litchi production.

He said Muzaffarpur`s Shahi Litchi is famous for its unique flavour and taste.

Five more children died of acute encephalitis syndrome (AES) Wednesday in Muzaffarpur district, taking the statewide death toll to 51 in the past 10 days.

Health officials said they had identified half a dozen districts where the disease has spread but the worst affected is Muzaffarpur, known for its sweet and juicy litchies.

Meanwhile, Bihar Health Minister Ramdhani Singh told reporters here that national and international scientific teams were camping in Muzaffarpur to ascertain the cause of the disease.

A team from the Atlanta-based Central Disease Control has come to the state after the centre`s intervention to help control the disease.

Ramdhani Singh said the state government has already appealed to the central government for assistance. He said the doctors treating the affected children informed him that the disease has not attained an epidemic form so far.